Solar cell module and manufacturing method thereof

ABSTRACT

A thin film based solar cell module having superior appearance without glittering, and method of manufacturing the same in a simple manner at a low cost are provided. The solar cell module includes a glass substrate  10  and a photo semiconductor element formed on a surface different from a light entering surface of glass substrate  10.  The glass substrate  10  is formed of a figured glass having recesses and protrusions formed to provide antiglaring effect, on the light entering surface. The photo semiconductor element is formed by successively stacking a transparent electrode  2,  a photo semiconductor layer  3  and a back electrode layer  5.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application NO. PCT/JP98/02715 which has an Internationalfiling date of Jun. 17, 1998, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a solar cell module and manufacturingmethod thereof and, more specifically, to a solar cell module used forsolar electricity generation and manufacturing method thereof.

BACKGROUND ART

Recently, new energy has been attracting attention in view ofenvironmental problems such as CO₂ increase and exhaustion of naturalresources, and, among others, solar electricity generation has beenconsidered promising. A solar cell module as the main component thereofincludes crystal based modules and thin film based modules.

The crystal based solar cell module is formed by arranging twenty tothirty crystal plates (wafers) of small area on a glass plate (coverglass) of which size corresponds to the size of the module, which areinterconnected to each other, and sealed and protected by a filler suchas EVA (ethylenevinyl acetate copolymer) and a back surface protectivefilm such as Tedlar (registered trademark).

In a thin film based solar cell module (solar cell module formed on asubstrate), a transparent electrode layer, a thin film semiconductorlayer and a back electrode layer are directly formed on a glass plate ofthe size of the module successively, respective layers are separated bypatterning means such as laser scribe, and connected so that desiredvoltage and current are obtained. As to sealing and protection, fillerand surface protective film similar to those used for the crystal basedsolar cell module are used. The thin film based solar cell modulestructured as described above is advantageous in view of cost ascompared with the crystal based solar cell module, in that the layercontributing to electricity generation is thin, that only one structuralmaterial is necessary, and that interconnection is simple.

As to the recent state of installment of the solar cell modules, it isnot often the case that a large number of solar cell modules are usedplaced side by side at a remote site for solar electricity generation,and in most cases, the modules are installed on a roof of a house orinstalled as roof integrated type solar cell modules which also functionas the house roof. Further, in these days, a so called grid connectionsystem comes to be widely popular in which the solar cell module isinstalled on the roof to generate power to be consumed by the house andto sell surplus power to an electric power company, and therefore solarelectricity generation systems developed for detached houses have beenincreasing. Such systems are developed on the premise that the solarcell module is installed on the roof of the house, and thereforeappearance of the building itself and coordination with other housestherearound are of importance. In such an environment, when the surfaceof the solar cell module is like a mirror reflecting sun light,neighbors and passers-by may make complaints about “glare” and“glittering.” Further, architects have pointed out the problem that whenthe module is used as the roof material, scenery and sky are reflectedon the surface of the module, impairing stylish appearance of thebuilding.

The following measures have been devised for these problems.

For example, for a crystal based solar cell module, use of a figuredglass as the cover glass has been proposed to cause random reflectionand diffusion of light at the surface of the cover glass. In fact,figured glass used as the cover glass solely for this purpose iscommercially available from AFG Industries Inc. of the United States,under the trade names of “Sunadex”, “Solite” and “Solatex”. Further, itis disclosed by General Electric Company in the 16th IEEE PhotovoltaicSpecialists Conference, 1982 (proceedings pp. 828-833) that thosefigured glasses were utilized for roof tile solar cell modules.

For the thin film based solar cell modules, sealing of sub modules smallin area by the structure similar to that of the crystal based solar cellmodules and use of the above described dedicated figured glass as thecover glass have been studied. Further, Japanese Patent Laying-Open No.6-45628, for example, proposes application of a resin containing beadsmixed therein for scattering light to the surface of the finished solarcell module.

The above described methods, however, involve more complicatedmanufacturing steps than the general method, when applied to the thinfilm based solar cell modules, and therefore the cost advantage of thethin film based solar cell modules described above will be lost.

The method of adhering the figured glass as a cover glass increasesweight, causes the problem of weather resistance of the adhesive resinfor adhesion, and lowers photoelectric conversion characteristic as-theamount of sun light reaching the solar cell decreases. Further, themethod of applying resin to the surface of the module causes the problemof weather resistance of the resin.

An object of the present invention is to solve various conventionalproblems experienced when the unsatisfactory appearance such asglittering as described above is to be prevented, and to provide a thinfilm based solar cell module of superior appearance free of glitteringor the like as well as to provide the method of manufacturing the samein a simple manner at a low cost.

DISCLOSURE OF THE INVENTION

The solar cell module in accordance with the present invention includesa glass substrate having first and second surfaces, and a photosemiconductor device formed on the first surface of the glass substrate,wherein the glass substrate is formed of a figured glass having recessesand protrusions formed to provide antiglare effect on the second surfacethrough which light enters, and the photo semiconductor device is formedof a first electrode layer, a photo semiconductor layer and a secondelectrode layer stacked successively.

Preferably, the photo semiconductor device may have the first electrodelayer, the photo semiconductor layer and the second electrode layerdivided into a plurality of areas, the second surface of the glasssubstrate may have arithmetic mean roughness Ra in the range of 50 μm to500 μm, and mean distance Sm of the recess and protrusion may be withinthe range of 0.1 mm to 10 mm.

Preferably, at least one of the first electrode layer, the photosemiconductor layer and the second electrode layer may be divided intothe plurality of areas by the step of laser patterning, and the secondsurface of the glass substrate may be formed to have arithmetic meanroughness Ra of at most 500 μm in that area which corresponds to 100 μmto 5000 μm in the periphery of the portion irradiated with laser in thestep of laser patterning.

More preferably, the second surface of the glass substrate may be formedto have arithmetic mean roughness Ra of at most 100 μm in the regioncorresponding to 100 μm to 5000 μm in the periphery of the portionirradiated with laser in the step of laser patterning.

The method of manufacturing a solar cell module in accordance with thepresent invention includes the steps of successively stacking a firstelectrode layer, a photo semiconductor layer and a second electrodelayer on a first surface of a glass substrate, and dividing the firstelectrode layer, the photo semiconductor layer and the second electrodelayer into a plurality of areas, wherein at least one of the firstelectrode layer, the photo semiconductor layer and the second electrodelayer is divided into the plurality of areas by the step of laserpatterning, the glass substrate is formed of a figured glass havingrecesses and protrusions for providing antiglare effect formed on asecond surface through which light enters, and the method furtherincludes, before the step of laser patterning, the step of placing atransparent material having index of refraction of 1.3 to 1.7 on atleast a portion to be irradiated with laser of the second surface of theglass substrate for smoothing the surface to be irradiated with laser.

Preferably, the method may further include the step of removing thetransparent material after the step of laser patterning.

Preferably, the index of refraction of the transparent material is 1.45to 1.55.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a first embodimentof the present invention.

FIG. 2 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 3 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 4 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 5 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 6 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 7 is a cross sectional view illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment.

FIG. 8 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a second embodimentof the present invention.

FIG. 9 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a third embodimentof the present invention.

FIG. 10 is an illustration related to a problem experienced inmanufacturing the solar cell module in accordance with the thirdembodiment.

FIG. 11 is a cross sectional view illustrating an example of the methodof manufacturing the solar cell module in accordance with the thirdembodiment employing the step of laser patterning, in accordance withthe present invention.

FIG. 12 is a cross sectional view illustrating an example of the methodof manufacturing the solar cell module in accordance with the thirdembodiment employing the step of laser patterning, in accordance withthe present invention.

FIG. 13 is a cross sectional view representing a schematic structure ofa portion of a solar cell module of a comparative example.

BEST MODES FOR CARRYING OUT THE INVENTION

In the following, a solar cell module having one stage of solar cellsincluding amorphous semiconductor connected in longitudinal direction,integrated in module plane and connected, will be described as anexample of the present invention.

FIG. 1 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a first embodimentof the present invention.

Referring to FIG. 1, the solar cell module includes a glass substrate10, a transparent electrode layer 2 formed on a surface different fromlight entering surface of glass substrate 10, a photo semiconductorlayer 3 formed on transparent electrode layer 2, and a back electrodelayer 5 formed on photo semiconductor layer 3 with a reflectionpromoting layer 4 interposed.

A photo transmitting material such as ITO, SnO₂ or ITO/SnO₂, which is astacked body of these, for example, may be used as transparent electrodelayer 2.

In the present embodiment, photo semiconductor layer is formed bysuccessively stacking a p type amorphous silicon semiconductor layer 31,an i type amorphous silicon semiconductor layer 32 and an n typeamorphous silicon semiconductor layer 33. The structure of photosemiconductor layer 3 is not limited to this, in the present invention.More specifically, as photo semiconductor layer 3, a semiconductor layerin which amorphous or microcrystal of amorphous silicon basedsemiconductor such as amorphous silicon a-Si, amorphous silicon hydridea-Si:H, amorphous silicon carbide hydride a-SiC:H, amorphous siliconnitride or the like, or an alloy of silicon and carbide, germanium, tinor other element is synthesized to pin type, nip type, ni type, pn type,MIS type, hetorojunction type, homojunction type, shot key barrier typeor combination thereof may be used.

Further, the photo semiconductor device formed by successively stackingtransparent electrode 2, photo semiconductor layer 3 and back electrodelayer 5 is divided into a plurality of areas Z as a trench is formed inat least any of the transparent electrode layer 2, photo semiconductorlayer 3 and back electrode layer 5 at the portion Y shown in FIG. 1,with respective areas Z being electrically connected to each other inseries or in parallel.

As the material of the glass substrate, soda lime glass such as blueplate glass and white plate glass, pyrex or borosilicate glass such aslow alkali glass of a little higher grade may be used. A figured glasshaving recesses and protrusions formed on the surface through whichlight enters is used as glass substrate 10. More specifically, surfaceroughness of the light entering surface of glass substrate 10 hasarithmetic mean roughness Ra within the range of 50 to 500 μm, with meandistance Sm between the recesses and protrusions is within the range of0.1 mm to 10 mm.

In the solar cell module having the structure shown in FIG. 1, in orderto attain sufficient antiglare effect to prevent unsatisfactoryappearance such as “glittering”, surface roughness of the light enteringsurface of glass substrate 10 should preferably have arithmetic meanroughness Ra value of at least 50 μm, and more preferably, at least 100μm. The value of the mean distance Sm between the recesses andprotrusions is preferably at most 10 mm and more preferably, at most 3mm.

As will be described later, considering that the photo semiconductordevice is divided into a plurality of areas in the step of laserpatterning, surface roughness of the light entering surface of glasssubstrate 1 should preferably have the arithmetic mean roughness Ravalue of at most 500 μm and more preferably, at most 100 μm. Further,the value of mean distance Sm between recesses and protrusions shouldpreferably be at least 0.1 mm and more preferably at least 1 mm.

The thin film based solar cell module structured in this manner surelyprovides desired voltage and current.

The method of manufacturing the solar cell module in accordance with thefirst embodiment shown in FIG. 1 will be described in the following.FIGS. 2 to 7 are cross sectional views illustrating the method ofmanufacturing the solar cell module in accordance with the firstembodiment shown in FIG. 1.

First, referring to FIG. 2, entirely on a surface different from thelight entering surface of figured glass 10 having prescribed recessesand protrusions formed on the light entering surface, transparentelectrode 2 is formed.

Thereafter, referring to FIG. 3, a prescribed position of glasssubstrate 10 with transparent electrode 2 formed is irradiated withlaser beam, so that a prescribed portion of transparent electrode 2 isremoved until glass substrate 10 is exposed, whereby transparentelectrode layer 2 is divided into a plurality of areas. The laser beammay be directed from the light entering surface side of glass substrate10 as represented by an arrow A, or may be directed from the side of thephoto semiconductor device forming surface, different from the lightentering surface, as shown by an arrow B.

Thereafter, referring to FIG. 4, on transparent electrode 2 and on glasssubstrate 10 exposed by laser irradiation, p type amorphous siliconsemiconductor layer 31, i type amorphous silicon semiconductor layer 32and n type amorphous silicon semiconductor layer 33 are stackedsuccessively. In the present embodiment, photo semiconductor layer 3 isformed by three layers, that is, p type amorphous silicon semiconductorlayer 31, i type amorphous silicon semiconductor layer 32 and n typeamorphous silicon semiconductor layer 33.

Thereafter, referring to FIG. 5, a prescribed position of glasssubstrate 10 having transparent electrode 2 and photo semiconductorlayer 3 formed is irradiated with laser beam, so that a prescribedportion of photo semiconductor layer 3 is removed until transparentelectrode layer 2 is exposed, whereby the photo semiconductor layer 3 isdivided into a plurality of areas. The laser beam may be directed fromthe light entering surface side of glass substrate 10 as represented bythe arrow A, or it may be directed from the side of the semiconductorelectrode forming surface different from the light entering surface asrepresented by the arrow B.

Thereafter, referring to FIG. 6, on photo semiconductor layer 3 andtransparent electrode 2 exposed by laser irradiation, reflectionpromoting layer 4 is formed and back electrode layer 5 is formed furtherthereon. Though reflection promoting layer 4 is interposed between photosemiconductor layer 3 and back electrode layer 5 in the presentembodiment, back electrode layer 5 may be formed directly on photosemiconductor layer 3.

Thereafter, referring to FIG. 7, a prescribed position of glasssubstrate 10 having transparent electrode 2, photo semiconductor layer3, reflection promoting layer 4 and back electrode layer 5 formedthereon is irradiated with laser beam so that a prescribed portion ofphoto semiconductor Layer 3, reflection promoting layer 4 and backelectrode layer 5 is removed until transparent electrode layer 2 isexposed, whereby photo semiconductor layer 3, reflection promoting layer4 and back electrode layer 5 are divided into a plurality of areas. Thelaser beam may be directed from the light entering surface side of glasssubstrate 10 as represented by the arrow A, or it may be directed fromthe side of the photo semiconductor device forming surface differentfrom the light entering surface, as represented by the arrow B.

Though photo semiconductor layer 3, reflection promoting layer 4 andback electrode layer 5 are removed by laser irradiation untiltransparent electrode layer 2 is exposed in the present embodiment, onlythe reflection promoting layer 4 and back electrode layer 5 may beremoved until photo semiconductor layer 3 is exposed.

Thereafter, a lead out electrode is attached to transparent electrodelayer 2 and back electrode layer 5, and the photo semiconductor deviceforming surface of glass substrate 10 is sealed and protected by using afiller such as EVA and a back surface protective film such as Tedler. Asthe filler, polyvinyl butyral or the like may be used other than EVA.EVA (index of refraction: 1.482), polyvinyl butyral (index ofrefraction: 1.48 to 1.49) and the like are designed to have the index ofrefraction close to that of soda lime glass (index of refraction: 1.51to 1.52), borosilicate glass (index of refraction: 1.47) or the likeused as the glass substrate.

By further attaching a terminal box and a frame to the solar cellobtained sealed in this manner, the solar cell module of the firstembodiment is completed.

FIG. 8 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a second embodimentof the present invention.

Referring to FIG. 8, in the solar cell module, of the light enteringsurface of glass substrate 20, an area X which corresponds to 100 μm to500 μm around the center which is irradiated with laser in the step oflaser patterning has arithmetic mean roughness Ra of at most 500 μm.

Other areas of the light entering surface of glass substrate 20 hasrecesses and protrusions formed to provide antiglaring effect.

The structure of the solar cell module in accordance with the secondembodiment other than this point is completely the same as the structureof the solar cell module in accordance with the first embodiment shownin FIG. 1, and therefore, description thereof is not repeated. Further,the method of manufacturing the solar cell module in accordance with thesecond embodiment is the same as the method of manufacturing the solarcell module in accordance with the first embodiment shown in FIGS. 2 to7, and therefore, description thereof is not repeated, either.

FIG. 9 is a cross sectional view representing a schematic structure of aportion of the solar cell module in accordance with a third embodimentof the present invention.

Referring to FIG. 9, in the solar cell module, arithmetic mean roughnessRa of the light entering surface of glass substrate 30 is larger than500 μm.

The structure of the solar cell module in accordance with the thirdembodiment except this point is the same as the structure of the solarcell module in accordance with the first embodiment shown in FIG. 1, andtherefore, description thereof is not repeated.

The method of manufacturing the solar cell module in accordance with thethird embodiment structured as above will be described.

FIG. 10 is an illustration showing a problem experienced inmanufacturing the solar cell module in accordance with the thirdembodiment.

Referring to FIG. 10, in the solar cell module in accordance with thethird embodiment, arithmetic mean roughness Ra of the light enteringsurface of glass substrate 30 is larger than the arithmetic meanroughness Ra of the light entering surface of glass substrate 10 in thesolar cell module in accordance with the first embodiment shown in FIG.1.

Therefore, when the step of laser patterning such as laser scribe isperformed as shown in FIGS. 2 to 7, the irradiated laser beam scattersat the recesses and protrusions formed on the light entering surface ofthe glass substrate. As a result, excessive laser energy is directedaround the portion to be laser-processed, resulting in degradation inquality or unnecessary processing of layers, or the laser energy may notbe concentrated to the portion to be processed, resulting in failure ofthe necessary process.

More specifically, when the laser beam is directed from the lightentering surface as represented by the arrow A in FIG. 10, the laserbeam reaching the light entering surface with recesses and protrusionsformed of glass substrate 30 scatters as represented by the arrows, sothat various portions are irradiated with the laser beam. As a result,laser processing of the portion to be processed may be insufficient,while unnecessary processing is done at portions of photo semiconductorlayer 3 and reflection promoting layer 4, possibly resulting in defects7 such as a pin hole or a short defect.

When the laser beam is directed from the photo semiconductor deviceforming surface as represented by the arrow B of FIG. 10, the laser beamreaching the light entering surface having recesses and protrusionsformed of glass substrate 30 is reflected at random as represented bythe arrows, whereby portions around the portion to be processed areirradiated. As a result, portions of the photo semiconductor layer 3 areunnecessarily processed, resulting in defects 6 such as a pin hole or ashort defect.

FIG. 11 is a cross sectional view illustrating an example of the methodof manufacturing the solar cell module in accordance with the thirdembodiment, employing the step of laser patterning while solving suchproblems.

Referring to FIG. 11, in the method, a leveling agent 81 for smoothingthe laser irradiation surface is applied at least to a portion to beirradiated with the laser, in the step of laser patterning such as laserscribe, so as to prevent scattering of light. As leveling agent 81, amaterial having index of refraction close to that of soda lime glass(index of refraction: 1.51 to 1.52) or borosilicate glass (index ofrefraction: 1.47) used as the glass substrate is used. Preferably, amaterial having index of refraction of 1.3 to 1.7 and more preferably,index of refraction of 1.45 to 1.55 is preferably used as the levelingagent. When a material having index of refraction of 1.45 to 1.55 isused as the leveling agent, for example, satisfactory edge can beobtained even when patterning of 100 μm in width is performed by laserscribe.

Preferably, transparent liquid, grease like material, or transparentresin like material allowing easy application before laser processing isused as the leveling agent. After laser processing, the leveling agentmay be left as it is or removed, and in view of safety, conditions ofprocess steps and the like, the material is appropriately selected, notlimited to the examples listed below. Further, the leveling agent may beapplied only to the portion to be laser-processed, or it may be appliedto the entire light entering surface of the glass substrate if the agentis to be removed after laser processing.

More specifically, examples of the leveling material which is solidmaterial and to be left after laser processing include vinyl acetateresin (index of refraction: 1.45 to 1.47), polyethylene (index ofrefraction: 1.51), polyester (index of refraction: 1.523 to 1.57),methyl methacrylate resin (index of refraction: 1.488 to 1.49), vinylchloride resin (index of refraction: 1.54 to 1.55) and polyvinyl alcohol(index of refraction: 1.49 to 1.55). Resin such as EVA (index ofrefraction: 1.482), polyvinyl butyral (index of refraction: 1.48 to1.49) or the like is designed to have the index of refraction close tothat of the glass substrate material and has been conventionally used asthe filler of the solar cell module, and therefore such resin isparticularly preferable, as it is readily available.

Examples of the leveling material which is liquid based material and tobe removed after laser processing includes o-xylene (index ofrefraction: 1.51), glycerin (index of refraction: 1.48), chlorobenzene(index of refraction: 1.52), tetrachloroethylene (index of refraction:1.51), carbon tetrachloride (index of refraction: 1.461) and etylbenzene(index of refraction: 1.5). Further, among liquids used in immersionmethod, which is the conventional method of measuring index ofrefraction of a crystal, 1,2-dibromopropane (index of refraction: 1.516)and a mixed liquid of terpentine oil and 1,2-dibromoethylene (index ofrefraction: 1.48 to 1.535) have been known as having index of refractionclose to 1.5, which can appropriately be utilized as the leveling agent.Further, water (index of refraction: 1.33) is easy to handle and safe,and therefore it is a particularly preferable leveling agent.

FIG. 12 is a cross sectional view illustrating another example of themethod of manufacturing the solar cell module in accordance with thethird embodiment employing the step of laser patterning.

Referring to FIG. 12, in this method, in the step of laser patterningsuch as laser scribe, laser irradiation is performed while the glasssubstrate 30 is immersed in water 91 contained in a container 92 withoutany lid. As described above, index of refraction of water is very closeto that of glass. Therefore, by this method, the laser irradiationsurface becomes smooth, as when the leveling material is applied in theexample of FIG. 11. As a result, scattering of light is prevented,ensuring satisfactory patterning.

Specific examples will be described in the following.

EXAMPLE 1

The solar cell module having the structure shown in FIG. 1 wasfabricated in the following manner.

As glass substrate 10, template-processed white plate glass (float glasswith ions removed) was used. Recesses and protrusions were formed on thelight entering surface of glass substrate 10 with the arithmetic meanroughness Ra of 3000 μm and mean distance Sm between recesses andprotrusions of 1 mm. The size of the glass substrate 10 was 450 mm×900mm, and the thickness was 4 mm, so as to maintain strength of themodule.

On a surface different from the light entering surface having recessesand protrusions formed thereon of glass substrate 10, an SnO₂transparent electrode layer 2 having the thickness of about 700 nm wasformed as shown in FIG. 2. The surface of the thus formed SnO₂ layer 2had recesses and protrusions of about 200 nm.

Thereafter, the thus formed SnO₂ transparent electrode layer 2 waspatterned by laser scribe, as shown in FIG. 3.

Thereafter, as shown in FIG. 4, photo semiconductor layer 3 was formedby parasitic CVD method on SnO₂ layer 2 and on exposed glass substrate10. More specifically, a p type amorphous silicon carbide hydridea-SiC:H layer 31 was stacked by decomposing SiH₄, B₂H₆ and CH₄, i typeamorphous silicon hydride a-Si:H layer 32 was stacked by decomposingSiH₄, and n type amorphous silicon hydride a-Si:H layer 33 was stackeddecomposing SiH₄ and PH₃, successively, to form photo semiconductorlayer 3.

Thereafter, the thus formed photo semiconductor layer 3 was patterned bylaser scribe as shown in FIG. 5.

Thereafter, as shown in FIG. 6, on the photo semiconductor layer and theexposed SiO₂ transparent electrode layer 2, reflection promoting layer 4of ZnO and back electrode layer 5 of Ag as high reflective metal werestacked by spattering.

Thereafter, the thus formed reflection promoting layer 4 and backelectrode layer 5 were patterned by laser scribe as shown in FIG. 7.

Finally, a lead-out electrode was attached to transparent electrode 2and back electrode 5, the semiconductor device forming surface wassealed and protected by using EVA and Tedler, and a terminal box and aframe were attached.

In this manner, the solar cell module having the structure shown in FIG.1 was obtained. In the solar cell module, the length of area Y where atrench was formed by laser scribe was about 300 μm, and the length ofeach area Z of the photo semiconductor device divided into a pluralityof areas was about 9 mm.

For laser scribe, laser irradiation was performed from the side of thelight entering surface of glass substrate 10 represented by the arrow Aand from the side of the photo semiconductor device forming surfacerepresented by the arrow B, of FIGS. 3, 5 and 7. As a result, it wasfound that satisfactory patterns could be formed no matter from whichside the laser irradiation was performed, and there was no problemexperienced in the step of laser patterning.

The solar cell module obtained in this manner was installed on a roof,and observed at a distance of 20 m. As a result, it was found thatsatisfactory appearance without glittering was attained.

Comparative Example 1

A solar cell module was fabricated in the similar manner as Example 1,using a common flat glass as the glass substrate.

FIG. 13 is a cross sectional view representing a schematic structure ofa portion of the thus obtained solar cell module.

Referring to FIG. 13, in the solar cell module, the light enteringsurface of glass substrate 40 did not have any recesses or protrusionsformed but was flat. The structure other than this point was the same asthe solar cell module of Example 1 shown in FIG. 1, and therefore,description thereof is not repeated.

The solar cell module obtained in this manner was installed on a roofand observed from a distance of 20 m. As a result, it was found thatscenery therearound was reflected because of mirror like reflection, andtherefore the appearance as the building material was unsatisfactory.

Comparative Example 2

A figured glass having recesses and protrusions formed on the lightentering surface with arithmetic mean roughness Ra of 600 μm and meandistance Sm between recesses and protrusions of 1 mm was used as theglass substrate, and the solar cell module was fabricated in the similarmanner as in Example 1.

As a result, when the laser beam was directed from the side of the photosemiconductor device forming surface, pin hole was generated because ofrandom reflection of light as shown in FIG. 10, resulting in shortdefect. When the laser beam was directed from the light entering surfaceside, portions other than desired were processed by scattering of lightas shown in FIG. 10, and patterning was not satisfactory.

Comparative Example 3

A figured glass having recesses and protrusions formed on the lightentering surface with arithmetic mean roughness Ra of 200 μm and meandistance Sm between recesses and protrusions of 0.05 mm was used as theglass substrate, and the solar cell module was fabricated in the similarmanner as in Example 1.

As a result, when the laser beam was directed from the side of the photosemiconductor device forming surface, pin hole was generated because ofrandom reflection of light as shown in FIG. 10, resulting in shortdefect. When the laser beam was directed from the light entering surfaceside, portions other than desired were processed by scattering of lightas shown in FIG. 10, and patterning was not satisfactory.

EXAMPLE 2

A figured glass having recesses and protrusions on that area of thelight entering surface which corresponded to 100 μm around a portionwhich was irradiated with laser in the step of laser patterning witharithmetic mean roughness Ra of 50 μm and mean distance Sm betweenrecesses and protrusions of 1 mm, and on other areas of the lightentering surface to provide antiglaring effect caused by diffusion oflight was used as the glass substrate, and the solar cell module wasfabricated in the similar manner as in Example 1.

For laser scribe, laser irradiation was performed both from the side ofthe glass substrate and from the side of the photo semiconductor elementforming surface. As a result, it was found that satisfactory patternscould be formed no matter from which side laser irradiation wasperformed, and no problem was experienced in the step of laserpatterning.

The solar cell module provided in this manner was installed on a roofand observed from a distance of 20 m. As a result, it was found thatsatisfactory appearance without glittering was attained.

EXAMPLE 3

A figured glass having a smooth texture comparative to a common flatglass in that region of the light entering surface which corresponded to100 μm around the portion irradiated with laser in the step of laserpatterning and having recesses and protrusions formed to provideantiglaring effect caused by diffusion of light on other areas of thelight entering surface was used as the glass substrate, and the solarcell module was fabricated in the similar manner as in Example 1.

For laser scribe, laser irradiation was performed both from the side ofthe light entering surface and from the side of the photo semiconductorelement forming surface of the glass substrate. As a result, it wasfound that satisfactory patterns could be formed no matter from whichside laser irradiation was performed, and no problem was experienced inthe step of laser patterning.

The solar cell module provided in this manner was installed on a roofand observed from a distance of 20 m. As a result, it was found thatsatisfactory appearance without glittering was attained.

EXAMPLE 4

A figured glass having the similar shape as that used in ComparativeExample 2 was used as the glass substrate, and the solar cell module wasfabricated in accordance with the method described with reference toFIG. 11.

More specifically, on that region which corresponded to 100 μm aroundthe portion irradiated with laser in the step laser patterning, carbontetrachloride as the leveling agent was applied and thereafter laserscribe processing was performed. After laser processing, the levelingagent was removed.

For laser scribe, laser irradiation was performed both from the side ofthe light entering surface and from the side of the photo semiconductorelement forming surface of the glass substrate. As a result, it wasfound that satisfactory patterns could be formed no matter from whichside laser irradiation was performed, and no problem was experienced inthe step of laser patterning.

The solar cell module provided in this manner was installed on a roofand observed from a distance of 20 m. As a result, it was found thatsatisfactory appearance without glittering was attained.

EXAMPLE 5

A figured glass having the similar shape as that used in ComparativeExample 2 was used as the glass substrate, and the solar cell module wasfabricated in accordance with the method described with reference toFIG. 12.

First, as shown in FIG. 12, laser irradiation was performed asrepresented by the arrow A while glass substrate 30 was immersed inwater 91 with the light entering surface facing upward. Thereafter,laser irradiation was performed while the glass substrate 30 wasimmersed in wafer 91 with the light entering surface facing downward. Inthis manner, laser irradiation was performed both from the side of thelight entering surface and the side of the photo semiconductor deviceforming surface of glass substrate 30. As a result, it was found thatsatisfactory patterns could be formed no matter from which side laserirradiation was performed, and no problem was experienced in the step oflaser patterning.

The solar cell module provided in this manner was installed on a roofand observed from a distance of 20 m. As a result, it was found thatsatisfactory appearance without glittering was attained.

Industrial Applicability

As described above, according to the present invention, a thin filmbased solar cell module with antiglare measure can be manufactured byslightly changing the process steps and material, other than the use ofa figured glass having prescribed recesses and protrusions formed on thelight entering surface in place of the common flat glass which has beenused conventionally as the glass substrate.

What is claimed is:
 1. A solar cell module, comprising: a glasssubstrate having first and second surfaces, and a photo semiconductorelement formed on said first surface of said glass substrate; whereinsaid glass substrate is formed of figured glass having recesses andprotrusions formed on said second surface through which light enters, toprovide antiglaring effect, said second surface having an arithmeticmean roughness Ra within the range of 50 μm to 500 μm and a meandistance Sm between recesses and protrusions within the range of 0.1 mmto 10 mm; and said photo semiconductor element is formed by successivelystacking a first electrode layer, a photo semiconductor layer, and asecond electrode layer, said first electrode layer, said photosemiconductor layer, and said second electrode layer being divided intoa plurality of areas.
 2. The solar cell module according to claim 1,wherein at least one of said first electrode layer, said photosemiconductor layer, and said second electrode layer is divided into aplurality of areas by a step of laser patterning, and an areacorresponding to 100 μm to 5000 μm around a portion to be irradiatedwith laser in a step of laser patterning of said second surface of saidglass substrate has an arithmetic mean roughness Ra of at most 500 μm.3. The solar cell module according to claim 2, wherein an areacorresponding to 100 μm to 5000 μm around a portion to be irradiatedwith laser in said step of laser pattering of said second surface ofsaid glass substrate has an arithmetic mean roughness Ra of at most 100μm.
 4. A method of manufacturing a solar cell module, comprising thesteps of: successively stacking a first electrode layer, a photosemiconductor layer, and a second electrode layer on a first surface ofa glass substrate; and dividing said first electrode layer, said photosemiconductor layer, and said second electrode layer into a plurality ofareas; wherein at least one of said first electrode layer, said photosemiconductor layer, and said second electrode layer is divided into aplurality of areas by a step of laser patterning; said glass substrateis formed of a figured glass having recesses and protrusions formed on asecond surface through which light enters, to provide antiglaringeffect; said method further comprising before a step of laserpatterning, a step of placing a transparent material having index ofrefraction of 1.3 to 1.7 on at least a portion to be irradiated withlaser of said second surface of said glass substrate for smoothing thesurface to be irradiated with laser.
 5. The method of manufacturing asolar cell module according to claim 4, wherein an index of refractionof said transparent material is 1.45 to 1.55.
 6. The method ofmanufacturing a solar cell module according to claim 4, furthercomprising the step of removing said transparent material after saidstep of laser patterning.
 7. The method of manufacturing a solar cellmodule according to claim 6, wherein an index of refraction of saidtransparent material is 1.45 to 1.55.